I just run OpenSUSE as my main system, run XP64 on VirtualBox and for gaming I have Vista 64. I gotta love my college for giving me free licenses lol =P.

I'd actually recommend anyone to take a look at OpenSolaris if you've got NVIDIA hardware since they provide full hardware acceleration. Also, OpenSolaris is quite the interesting, and it's great for those who want true UNIX without the cost...

As for 64-bit vs. 32-bit, Crysis runs a lot better on my system using the 64-bit binary than the 32-bit version. I need 64-bit to use full 4GB.